Computer controlled railway brake equipment

ABSTRACT

A computerized locomotive control system receiving as inputs electrical signals representing automatic and independent braking control signals and a computer for determining, from said input signals, electrical signals representing desired equalization reservoir pressure, desired independent application and release pressure and desired actuating pressure. Electro-pneumatic valves controls the pressure in the equalization reservoir, on the independent application and release pipe and as the actuating pipe in response to the desired pressure signals. A electro-pneumatic valve for the control reservoir of the locomotive brake is controlled by the computer in response to pipe pressures. The computer provides penalties and interlocks electrically.

This is a continuation of application Ser. No. 07/984,100, filed Dec. 1,1992 which is a continuation of application Ser. No. 07/447,816, filedDec. 8, 1989, now U.S. Pat. No. 5,172,316 issued Dec. 15, 1992.

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates generally to novel and improved brake equipmentfor rail vehicles and more particularly to computer controlled brakeequipment located on the locomotive and arranged to control theapplication and release of the brakes of such locomotive, any trailinglocomotive, and any cars coupled to either.

Prior art brake equipment for locomotives has typically been implementedwith mechanical and pneumatic hardware, as, for example, the 26-L brakeequipment of New York Air Brake Company of Watertown, N.Y. Asillustrated in FIG. 1, this prior art brake equipment employs as majorcomponents a 26-C brake valve 30 including an independent brake valveSA-26, a 26-F control valve 33 and a J relay valve 37 interconnectedwith various pneumatic pipes represented by solid lines. The brake valve30 responds to movement by the train operator of an automatic brakehandle 31 to regulate pressure in a brake pipe 40 by means of anequalization reservoir 36 and a brake pipe relay in the brake valve 30for application and release of brakes on the locomotive, the brakes ofany trailing locomotive and the brakes of cars coupled to either (trainbrakes).

The automatic brake handle has six positions as illustrated by thesector diagram in FIG. 2 and defined as follows:

a) The Release position is for charging the brake equipment andreleasing the train brakes.

b) In the Minimum Reduction position, brake pipe pressure is reduced aminimum amount so as to initiate quick service on the train brakes(typically 4-6 psi brake pipe reduction), and lightly apply the trainbrakes.

c) The sector or zone between the Minimum Reduction and Full Servicepositions is the service zone. As the automatic brake valve handle ismoved through this zone from Minimum Reduction toward Full Service,brake pipe pressure is reduced proportionally to 23-26 psi with thehandle at the Full Service position, a full service brake application isobtained.

d) In addition to providing full service brake application as with thebrake valve handle in the Full Service position, Suppression ofoverspeed control and safety control application is obtained in thesuppression position.

e) The handle is movable to the Handle Off position as for trailingunits of a multiple unit locomotive or for locomotive's being towed"dead" in a train. The handle off position is also used for"overreductions" allowing brake pipe to be reduced further thanattainable in the Full Service position. Thus assuring full train brakeapplications.

f) The Emergency position is used for making brake valve emergency brakeapplications and results in brake pipe exhaust and brake pipe venting atthe highest rate of reduction.

The brake valve 30 also responds to movement of an independent brakehandle 32 by the train operator to control the application and releaseof the locomotive brakes independently of the train brakes and forreleasing an automatic brake application of the locomotive independentlyof the train brakes by way of the 26-F control valve 33 and the J relay37.

The independent brake handle 32 has two extreme positions, Release andFull Application separated by an application zone as shown in FIG. 2. Asthe handle is moved from the Release position through the applicationzone toward the Full Application position will apply the locomotivebrakes. The independent handle 32 can be depressed so as to cause therelease of any automatic brake application existing on the locomotive(due to operation of the automatic brake handle 31). This is effectedvia the 26LC brake valve 30 and the 26-F control valve 33. If theindependent brake handle 32 is in an Application position, thelocomotive brake will be applied according to the higher of independentor automatic brake.

The 26-F control valve 32 and auxiliary reservoir 36 respond to serviceand emergency rates of brake pipe pressure reduction (brakeapplications) to control the locomotive brake cylinder pressure via theJ relay valve 37. The 26-F control valve 33 also responds to a brakerelease operation of the independent brake handle 32 to controllocomotive brake cylinder pressure to release the locomotive brakesfollowing an automatic brake operation at the service rate developed byoperation of the automatic brake handle 31. A key element of the 26-Fcontrol valve 30 is a double check valve 34 which applies to the J relayvalve 37 the higher of the pressures developed by the 26-F control valve33 or by the independent application and release pipe 42.

The J relay valve 37 is a volume amplifier that operates to translatethe pressure at a smaller volume input to a desired pressure at a largervolume output. As the desired output pressure can differ for differentlocomotive (different sized brake cylinders), it has been necessary toselect a particular J relay valve for a particular locomotivespecification.

The P2-A valve 35 is a brake application or penalty valve responsive tounsafe conditions to effect brake application at the full service rate.For instance, the P2-A valve is illustrated as responding to anoverspeed condition and/or to a foot pedal fault (absence of footpressure on the foot pedal).

The brake equipment also includes a multiple unit valve 38 enabling thelocomotive to be united with other locomotives as either a lead, trailor dead unit. The multiple unit valve 38 of a lead unit serves to signaltrail units via independent brake application and release pipe 42 and anactuating pipe 43. In the lead position, multiple unit valve 38 connectsthe actuating pipe signal from brake valve 30 to the control valve 33and actuating pipe 43 and connects the independent application andrelease signal from the brake valve 30 to the independent applicationand release pipe 42.

The prior art brake equipment is costly to manufacture as it requiressubstantial iron and aluminum castings for each of the pneumatic valvesand is costly to install as it requires numerous pipe interconnections.

Computerized brakes are well known as shown by U.S. Pat. No. 4,402,047to Newton et al. In this computerized brake control system, the computercalculates the desired brake cylinder pressure from commanded brakesignals, vehicle weight, vehicle speed and dynamic braking and comparesthe desired brake cylinder pressure with the actual brake cylinderpressure. Then it controls the fluid brake system to cause the actualbrake pressure to be substantially equal to the desired brake pressure.As illustrated in FIG. 2 of that patent, the brake control manifold 40has an electromagnetically controlled apply valve 46 and release valve48 under the control of computer to cause the desired brake cylinderpressure to match the desired brake cylinder pressure.

Another system which shows the use of magnetic valves for applying andreleasing brake pressure is U.S. Pat. No. 4,652,057 to Engle, et al.Single control handle 76 is used in combination with a control panel 102and a display 96. In both systems, the electromagnetically controlledvalves control the specific pressure applied to the brake cylinders froma reservoir and does not control the pressure within the reservoir.

Prior systems have also included a substantial amount of fluid tubingwhich is costly to build and maintain. Similarly the interlocks betweenthe propulsion and braking system have been mechanical and also afunction of the operator.

Thus this is an object to present invention to provide a novel computerinterfaced for a computer controlled rail brake equipment.

Another object of the present invention is to provide a braking systemwhich will guarantee full service application for any initial computerbrake pipe pressure charge. A further object is to providestandardization of locomotive hardware that would not require alternateparts.

Still a further object of the present invention is to provide a computercontrolled railway brake system with improved interlocks.

These and other objects of the present invention are achieved byproviding a computerized locomotive control system receiving as inputselectrical signals representing automatic and independent brakingcontrol signals and a computer for determining, from said input signals,electrical signals representing desired equalization reservoir pressure,desired independent application and release pressure and desiredactuating pressure. A first electro-pneumatic valve controls thepressure in the equalization reservoir in response to the desiredequalization pressure. A second electro-pneumatic valve controls thepressure on the independent application and release pipe in response tothe desired independent application release pipe pressure signal. Athird electro-pneumatic valve controls the pressure on the actuatingpipe in response to the desired actuating pressure signal. Thus thesystem has basically used a computer to emualate the 26C brake valveusable with automatic and standard independent brake handles.

Input signals are provided representing predetermined equalizingreservoir release pressure. The computer determines a corresponding fullservice pressure from the predetermined equalizing reservoir releasepressure and determines a proportional desired equalizing reservoirsignal in the range between the equalizing reservoir's predeterminedrelease and corresponding full service pressures from the automaticbraking control signals. Thus the braking signal is proportional to thepredetermined reservoir release pressure and not dependent merely on thebrake handle position. This improves train brake handling by making theFull Service brake position actual full train brake application.

The system also includes a fourth electro-pneumatic valve forcontrolling the pressure in the control reservoir. The computerdetermines the desired control reservoir pressure from pipe pressuresalone or in combination with braking control signals to control thefourth electro-pneumatic valve. Electric signals representing brake pipepressure, the independent application and release pipe pressure and theactuating pipe pressure are provided to computer.

The computer also receives electrical signals identifying the brakecylinder valve and uses this in determining the appropriate reservoirpressure. This allows the combination for J relays of variouscapacities. The locomotive brake cylinder circuit also includespneumatic circuit for pneumatically controlling the brake cylinder byapplying and releasing emergency pressure independent of the controlreservoir as well to limit the brake cylinder pressure. A fluidswitchover circuit is also provided determining whether the fourthelectro-pneumatic valve or the brake pipe will control pressure in thecontrol reservoir. A brake pipe disconnect valve is also provided inresponsive to the switchover to disconnect the brake pipe valve from thebrake pipe.

The computer also receives electrical signals representing a penaltycondition and determines a service brake application pressure as thedesired equalization reservoir pressure in response to a penaltycondition. Additionally an electromagnetic cut-off valve is provided andcontrolled by the computer in response to an emergency brake applicationto cut-off the brake pipe from the brake pipe valve. If the train is inthe trailing mode, the computer also disconnects the brake pipe valvefrom the brake pipe using the cut-off control.

As safeguards, the computer determines, for absence of an automaticbraking control signal, a service reduction of a desired equalizingreservoir pressure signal to at least the full service application. Thecomputer also determines, for absence of an independent brake controlsignal, a brake release desired independent release pressure signal. Thefirst electro-pneumatic valve reduces the pressure in equalizingreservoir to at least full-service for absence of a desired equalizationreservoir pressure. Second and third electro-pneumatic valves lap forabsence of a desired independent application and release pressure signaland actuating signal respectively.

The computer also provides a plurality of electrical interlocksdepending upon the position of the handles as well as ignoring theposition of the handles. Upon determination of an emergency brakingcondition, the computer transmits an idle condition signal for thethrottle and will not transmit any propulsion signals until the throttlehandle is also placed in the idle position. The computer also delays thetransmission of predetermined signals from the throttle when switchingbetween propulsion and dynamic braking. Also, the computer, when thethrottle handle switches from forward to reverse, prevents transmittingpropulsion control signals until the locomotive speed in below apredetermined speed. If the computer senses that the locomotive is beingswitched between the leading and trailing modes, it does not transmitany control signals until the position control signals represent neutralor idle positions for the automatic and interdependent brake controlsand the throttle. Also in switching between leading and trailing modes,the locomotive speed must be zero.

As with the braking signal, the computer can determine a proportionalpropulsion signal between zero and an inputted maximum speed for theappropriate throttle position. If the system is set for the trailingmode, the computer does not produce any propulsion or dynamic brakingsignals. The computer can also be programmed to produce automatic speedcontrol.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a pneumatic brake system of the prior art.

FIG. 2 is a schematic representation of the control handles of themaster control stand including the automatic braking, independentbraking and the throttle handles.

FIG. 3 is a schematic representation of a locomotive control systemincorporating the principles of the present invention.

FIG. 4 is a view of the touch screen display according to the presentinvention.

FIG. 5 is a block diagram of a computer controlled railroad locomotivebrake equipment incorporating the principles of the present invention.

FIG. 6 is a block diagram of the brake pipe control incorporating theprinciples of the present invention.

FIG. 7 is a block diagram illustrating the brake cylinder controlincorporating the principles of the present invention.

FIG. 8 is a block diagram of the independent brake control incorporatingthe principles of the present invention.

FIG. 9 is an electrical block diagram illustrating the throttle anddynamic braking control incorporating the principles of the presentinvention.

FIG. 10 is an electrical block diagram illustrating the signaling andsanding control incorporating the principles of the present invention.

FIG. 11 is a block diagram illustrating the overall program for alocomotive control according to the present invention.

FIG. 12 is a block diagram illustrating the locomotive control portionof FIG. 11.

FIG. 13 is a flow chart of the control brake pipe portion of the FIG.12.

FIG. 14 is a flow chart for the control brake pipe valve portion of theprogram of FIG. 13; and

FIG. 15 is a flow chart of the control brake cylinder portion of FIG.12.

DETAILED DESCRIPTION OF THE DRAWINGS

A computerized locomotive control system of the present invention isillustrated in FIG. 3. It should be noted that in the Figures the fluidlines of the pneumatic system will be illustrated by solid lines whereasthe electrical interconnections will be illustrated by dash lines.Wherever possible the elements, for example the trainlines and thecontrol handles, in the Figures will have the same numbers as those ofthe prior art described in FIGS. 1 and 2. A master control stand 50includes the automatic brake handle 31, the independent brake handle 32and the throttle 39. The locomotive includes the brake pipe 40, themaster reservoir equalization pipe 41, the independent application andrelease pipe 42, actuating pipe 43, and a 27-wire multiple unitelectrical trainline 44. The standard pair of venting valves 46 areprovided on the brake pipe 42.

The master control stand 50 is fluidly connected to the brake pipe 40 soas to directly apply an emergency condition fluidly to the brake pipe. Aconductor valve 49 is also connected to the brake pipe 40 to apply anemergency condition. The master control stand 50 is electricallyconnected to the microcomputer 56 as are touch screen display 52 and anauxiliary control stand 54. Microcomputer 56 is connected to thepropulsion package 45, which is a standard prior art propulsion package,and both are connected to the 27-wire trainline 44 for electricallycommunicating with the other locomotives on the train.

An electro-pneumatic interface control valve 60 between themicrocomputer 56 and the pneumatic braking system is shown as includingthe brake control portion 62 and an auxiliary portion 64 both connectedto pipe bracket 63. Interface control valve 60 provides all thefunctions of the control of the brakes, both pneumatically andelectrical signalling, and for auxiliary controls. The pipe bracket 63is a connection of all pipe interfaces which provides a unitized valvefor simplification of maintenance. The pipe bracket has the requiredreservoir for brake operations and contains disposable filters for thepneumatic inputs. The brake control portions 62 provides for all brakingportions found on the locomotive. This controls the brake pipe 40, thebrake cylinder of the locomotive 66, independent brake pipe 42 andactuating pipe 43. It provides all the required electrical interfacesfor the operation of the brake system. The auxiliary portion 64 providespneumatic controls for the special functions. This may be for thesanding, pneumatic horns, bells etc. . . Auxiliary portion 64 operatesindependent of the brake valve. A first main reservoir 47 is connectedto the main reservoir equalization pipe 41 as is a second main reservoir48. The second main reservoir 48 is connected to the electro-pneumaticinterface control valve 60.

The system of FIG. 3 is a simplification of the controls byconsolidating the numerous engineer control devices in a centrallocation. Controls have been consolidated into a three handle mastercontroller unit 50 and a touch screen display 52. All of the normaltrain operation will be obtainable through these two devices. A fuelpump, engine run, headlights, auxiliary lights and heater controls arenot incorporated into the microcomputer 56 since they would not simplifythe operation. These functions are in the auxiliary control stand 54.

The pneumatic brake control devices that had to be of a mechanicalnature is simply accomplished by a computer logic. The resultingreduction of pneumatic control devices, allows the consolidation ofbrake control into a unitized package. Required periodic brake overallcan now be accomplished through the removal and rebuilding of a singlevalve package. The maintenance will also be simplified by diagnosticcapabilities under computer control. Faults can be pinpointed anddisplayed to the maintenance personnel.

Other than the single pneumatic control between the master control stand50 and the brake pipe 40 to provide an emergency brake applicationdirectly to the brake pipe 40, the master control stand 50 is connectedto the pneumatic part of the brake system through the microcomputer 56.All handles are independent of each other and their is no mechanicalinterlock between the handles. The interlock is electrically provided bythe microcomputer 56 thereby simplifying the master control stand 50. Inthe trail mode or cutout positions, the handles 31, 32 and 39 are freeto be moved and will produce no action through a computer lockout. Theonly action is the emergency brake application produced pneumatically.The computer 56 is still responsive to the 27-wire trainline 44 and thepipes to provide appropriate controls even in the trail mode.

The automatic brake handle 31 provides an analog signal to themicrocomputer 56 to the level of command brake or special commands asshown in FIG. 2. The Release position provides maximum level of theanalog signal to the microcomputer 56 to charge the brake pipe fully orautomatically release the brakes. The Minimum brake application positionprovides a linear decrease in its analog output signal proportional tothe extremes between release and emergency positions. This signals themicrocomputer 56 to reduce the brake pipe pressures sufficient toinitiate quick service and set the brakes on the cars. This is generallya 4 to 6 psi brake pipe reduction. The Full Service brake applicationposition provides a further decrease in its analog signal. movement ofthe handle 31 from the Minimum position signals the computer to furtherreduce the brake pipe 40 proportional to the handle position up to theFull Service or maximum service brake position.

The microcomputer 56 controls the brake pipe 40 in such a manner thatthe Full Service position is the maximum service brake available for theinitial brake pipe setting. As will be discussed more fully below, thecomputer has the capability of proportioning the brake pipe signals as afunction of release minimum service to a full service application basedon the initial brake pipe setting. This overcomes a substantial numberof the problems of the prior as discussed above.

A Suppression position is provided on a standard automatic handle 31 andmay be ignored by the computer logic. It is only provided for theengineers convenience. The purpose of the Suppression position is toindicate that the handle is in Full Service to the overspeed and/orsafety control logic, therefore the Full Service position is sufficientfor this purpose. The Handle Off position is also not required but maybe used to signal to the microcomputer 56 to reduce the brake pipepressure to zero. The Emergency position has the least analog output andsignals the microcomputer 56 that an emergency reduction of the brakepipe is required. This position mechanically sends the brake pipedirectly to atmosphere and results in an emergency applicationregardless of state of the computer or cut-off device to be describedlater.

Although the movement of automatic brake handle from Full Servicetowards Release may increase analog signal, microcomputer 56 will notreact. Brake pipe charge or brake release command may only be achievedin the Release position. If preferred, the logic can be changed to allowgradual brake release for passenger service operation. Failure of theautomatic brake handle 31 or loss of the analog signal will result in anull output from the master control stand 50. The microcomputer 56 willinterpret this as a reduction of the brake pipe to zero at a servicerate. This is the same command as the Handle Off position.

The independent brake handle 32, which provides independent control overthe locomotive brake versus the train brake of the automatic brakehandle 31, also provides an analog output signal to the microcomputer 56proportional to handling extreme positions. Unlike the automatic brakehandle 31, loss of an analog signal from the independent brake handle 32results in releasing the locomotive brake and does not result in a brakeapplication as in the independent brake handle failure. Thus theengineer has the option of completing the run or moving to a sidetrackfrom the leading cab. Independent brake handle 32 moves between theRelease position as a minimum analog output signal to the Full positionwhich has the maximum analog output signal. This movement will result ina fully variable analog output signal in either direction and a fullyvariable increase and decrease of pressure in the independentapplication and release pipe 42 under the command of the computer 56.

A modification of the independent brake handle 32 is illustrated in FIG.3 as having a button 32b which actuates a momentary switch. The pressingof button 32b is a command to pressurize the actuating pipe 43. Releaseof the button will vent the actuating pipe 43. This provides the"bail-off" feature of the automatic brake and if the button iscontinuously depressed, "bailoff" of an emergency brake. This is to bedistinguished from the prior art wherein the independent brake handle 32itself had to be physically depressed to effectuate this functionmechanically and pneumatically.

The throttle 39 is a control for the 27-wire trainline 44 for power anddynamic braking. Detail of the microcomputer interface with the 27-wiretrainline 44 will be discussed later with respect to FIGS. 8 and 9 andonly summarized here.

FIG. 2 also illustrates the third master control stand handle 39 whichis the throttle. As shown in FIG. 2, the throttle 39 includes thestandard 1 to 8 propulsion positions as well as the dynamic brakingwhich goes from a set position to a maximum. Between the propulsion andthe dynamic braking portion is the Idle position and a Stop Engine offposition. The throttle lever 39 provides an analog output signalproportional to handle position with the maximum output representingmaximum power. The microcomputer 56 reads the propulsion detents 1-8 andprovides appropriate signals on the 27-wire trainline 44. It alsomonitors the Idle, Set and Dynamic braking positions. In the Stopposition, a shutdown of the engines is provided as a digital signal thatcircumvents the microcomputer 56. Whereas the automatic brake handle 31and Independent brake handle 32 are of standard configurations, thethrottle 39 is a new and distinctive control handle.

The touch screen display 52, as illustrated in FIG. 4 has three basicfunctions. It provides an indication of all of the status of the traincontrols, it provides switching functions by the touching of the screen,and it provides special messages to the engineer. With locomotive in thecut-out or trail mode, the screen is blank. Activation or cut-in of thelocomotive brings up the control screen display.

The touch screen display 52 has four distinct zones. The lower zone isfor the touch sensitive control switches including eighteen switches.There may be either momentary or latching switches according to softwarecontrol. When activated the selected function will be shaded or filledin. The touch zone also has Reverser, Power Reduction and Cruisefunctions located on the top of the zone. The digital indicator zoneprovides indications normally accomplished by lamps. There are eighteenpossible indications given by shading or filing of blocks. The messagezone is an information zone provided to the engineer by themicrocomputer 56. These may be for informational purpose only oroperation instruction or fault occurrences. The variable indicator zoneprovides an indication that would normally be displayed by gauges.Amperage, flow and acceleration are shown as bar graphs.

The display is used as a prompt to instruct the operator. For examplewhen the master control stand 50 is keyed in, and placed in the leadmode, the display will be presented to the engineer. This will enableall monitoring functions. The master controller handles positions willnot be active until handles are placed in the proper positions (Idle,Set, Release). A message may appear to that effect. All switching orcommand options will be in off or disabled mode. Also as an interlock,the forward/reverse selection on the touch panel must be made with thethrottle handle 39 in the Idle position. In addition to the interlocksproduced by computer determination, Brake pipe cut-off and dynamicBraking cut-out may be manually determined by appropriate selection onthe touch screen display 52.

Power Reduction is activated by selecting either the Local or the MUtouch sensitive area. This would automatically bring the power to a 100%or maximum. The engineer then selects the proper arrow to reduce power.The power may also be increased in a like manner. The Cruise may beactive by selecting the Cruise On area. The Power Reduction must be offprior to the selection of the Cruise function. This will bring thecurrent miles per hour set speed within the Cruise window. The speed isthen set by the arrows to increase or decrease. Selecting Enable willactivate the Cruise control. Pushing the Enable will deactivate thecontrol but not turn the control off. The speed setting may be changedand then the control reactivated by the Enable. Off must be selectedprior to activation of the Power Reduction control.

An overview of the brake control portion 62 of the interface controlvalve 60 will be described with respect to FIG. 5. The brake controlportion 62 is connected to main reservoir MR, the main reservoirequalization pipe 41,and exhaust EXH as well as the equalizationreservoir 36,the control reservoir 65, and the auxiliary reservoir 68pneumatically. It also provides a pneumatic output to the brake cylinderBC, 66, the brake pipe 40, the independent application and release pipe42 and the actuating pipe 43.

Brake control portion 62 receives electrical control signals for theequalization reservoir pressure, brake pipe cutoff valve, the controlreservoir pressure, the independent application and release pipepressure and the actuating pipe pressure from the microcomputer 56.Inputs to the microcomputer 56 includes the automatic brake andindependent brake electrical signals from the master control stand 50,penalty inputs from standard penalty devices as electrical signals aswell as a group of electrical feedback signals. These feedback signalsfrom pressure sensors in FIGS. 5, 6, 7 and 8 include brake pipe pressure70, emergency cutoff pressure 71, equalization reservoir pressure 72,control reservoir pressure 74, brake cylinder pressure 73, actuatingpipe pressure 76 and independent application and release pipe pressure75.

The circuitry for the brake pipe control 80 of the brake control portion62 of the interface control valve 60 is illustrated in FIG. 6. Brakepipe control 80 is connected to the second main reservoir 48 through afilter 67. Equalization reservoir 36 has its pressure controlled by theequalization reservoir pressure controller 82 under the command of themicrocomputer 56. The pressure of the equalization reservoir 36 ismeasured by a pressure sensor 72 and fed back to the microcomputer 56.The value of the pressure in the equalization reservoir 36 is providedto the brake pipe relay 84 which will transmit a portion of the mainreservoir's 48 pressure to the trainline brake pipe 40 through brakepipe cutoff 86 and tow cutoff 88. The brake pipe cutoff 86 is anelectro-pneumatic device under the control of the microcomputer 56 andthe tow cutoff 88 is manually controlled. Brake pipe pressure sensor 71and emergency pressure cutoff sensor 70 are also shown in FIG. 6.

The brake pipe control 80 is active only if the locomotive is in thelead or keyed in mode. The control of the brake pipe control 80 issimilar to the number 26 brake equipment in that a reference volume orequalization reservoir 36 is used. The design is fail safe in thatfailure of that device results in a service brake application. In theevent of total failure of the microcomputer 56, a service brakereduction rate will occur.

The equalization reservoir pressure controller 82 is anelectro-pneumatic device which operates to control the referencepressure within the equalization reservoir 36. The output pressure islimited to a maximum of 90 psi. Any higher pressure may be manuallyadjusted by means not shown. The equalization reservoir pressurecontroller 82 controls the pressure in the equalization reservoir 36fully from zero psi to the maximum adjustable limit. Loss of controlsignal from the microcomputer 56 will result in a reduction of theequalization reservoir to zero psi at a service rate by the equalizationreservoir controller 82. The engineer may set the release equalizationmaster control stand 50.

As is well known, the brake pipe relay 84 is a pneumatic device thatmonitors the pressure within the equalization reservoir 36 andduplicates its pressure level to the output for the brake pipe 40. Onequalization reservoir 36 pressure reduction, the brake pipe relay 84will exhaust brake pipe 40 at a controlled service rate. The brake piperelay 84 and the equalization reservoir pressure controller 82 are selfmaintaining. The brake pipe cutoff 86 is a digital electro-pneumaticdevice which prevents the brake pipe charging or exhaust a) when thelocomotive is in the trial mode b) in the event of an emergency brakeapplication, c) during brake pipe leakage tests as con, handed from theengineer and d) for hostling operation. The brake pipe cutoff device 86is under the control of the microcomputer 56 and a null signal is acut-in command. Failure of the microcomputer 56 will result in thereduction of the brake pipe 40 at a service rate thereby applying thebrakes of the train.

As previously noted, the brake pipe pressure sensor 71 and the emergencycutoff pressure sensor 70 monitor the brake pipe 40. The brake pipesensor 71 provides a signal of the actual pressure in the brake pipe 40whereas the emergency cutoff sensor 70 need only monitor the emergencybrake application. Thus the two different devices provide distinct andindependent signals.

The tow cutoff device 88 is a manually operated pneumatic device. Itwill prevent any supply or exhaust of the brake pipe 40 for haul of thelocomotive with an inoperative microcomputer 56. This devices functionis integral in operation with the tow cutout 92 of the triple valve tobe discussed in the brake cylinder control 90 of FIG. 7.

The circuit for the brake cylinder control 90 of the brake controlportion 62 of the interface control valve 60 is illustrated in FIG. 7 ashaving an input from the second main reservoir 48 through common filter67 to the control reservoir controller 91. The control reservoirpressure controller 91, under control of computer 56, determines thepressure in control reservoir 65 which is sensed by the controlreservoir pressure sensor 74 and provided as an input to themicrocomputer 56. The control reservoir pressure controller 91 isconnected to the control reservoir 65 through the tow cutout or switchover device 92 which is manually controlled in common with the towcutoff device of FIG. 6. A triple valve 93 connects the brake pipe 40and the auxiliary reservoir 68 to the tow cutoff device 82. The outputof the tow cutoff device 82 is connected to the brake cylinder relay 37through a double check valve 96. The second input to the double checkvalve 96 is an emergency valve 95 which receives on its controllinginput the brake pipe pressure on brake pipe 40 or the pressure from theactuating pipe 43. The higher the two signals is provided by the doublecheck valve 94 to the emergency valve 95.

The higher value of the output of the emergency valve 95 and the towcutoff 92 is provided by the double check valve 96 to the brake cylinderrelay 37 on its control input. The main reservoir 48 is the supply inputto the emergency valve 95 and the brake cylinder relay 37. The output ofthe brake cylinder relay 37 is connected to the brake cylinder 66. Thepressure of the brake cylinder 66 is measured by the brake cylinderpressure sensor 73 and provided as an input back to the microcomputer56.

Service brake cylinder pressure is controlled solely by themicrocomputer 56 under normal operating conditions. Emergency brakepressure is pneumatically controlled, circumventing any con, hand of themicrocomputer 56. The tow cutout 92 in combination with the triple valve93 provides for pneumatic control service brake for tow of a faultylocomotive.

The control reservoir pressure controller 91 is an electro-pneumaticdevice to control the reference pressure in the control reservoir 65.The microcomputer 56 control the output pressure electrically forcommand of automatic service brake level. The control is fully variablefrom zero psi to main reservoir pressure. Upon loss of controllingsignal to the control reservoir pressure controller 91, results in arelease of the pressure in the control reservoir 65 and thereby releaseof the locomotive brake 66. This prevents dragging of the locomotivebrakes.

In the preferred embodiment, the microcomputer derives the control, forthe control reservoir pressure controller 91 from sensed pipe pressuresignals from the brake pipe 40, independent application and release pipe42 and actuator pipe 43. The train braking signal on these three pipesare produced by the brake control portion 62 on this or anotherlocomotive and the microcomputer 56 on all locomotives respond to thesame pipe pressure signals at the same time. As an alternative, themicrocomputer 56 could derive the controls for the control reservoirpressure controller 91 from the master stand 50 if the locomotive is inthe lead mode. This is not preferred since appropriate time delays wouldhave to be present to prevent the lead locomotive from applying itsbrakes before the remainder of the train.

In the event of an emergency brake signal on the brake pipe 40, theemergency valve 95 actuates pneumatically a loss of brake pipe pressure.The emergency valve 95 supplies a preset pressure output from the mainreservoir 48 directly to the control port of the brake cylinder relay 37negating any command pressure on the other input of the double actingcheck valve 96 from the microcomputer controlled reservoir 65. Thisemergency pressure output command may be removed to release thelocomotive brake 66 by pressurizing the actuating pipe 43. This signalon actuating pipe 43 through double check valve 94 changes control inputof emergency valve 95. The double check valve 96 also limits the outputpressure from the control reservoir 65 to the emergency pressure leveland prevents a malfunction of the control reservoir pressure controller91.

On the failure of the microcomputer 56 for any cause, the triple valve93 is included to tow the locomotive. The triple valve 93 will provideautomatic service brake control pressure and is a displacement valvebrake control device. To switch over from the reservoir pressurecontroller 91 to the triple valve 93 as a controller for the controlreservoir 65 is under the control of the tow cutoff 92.

The triple valve 93 charges the auxiliary reservoir 68 at a controlledrate within the value of the brake pipe 40 pressure. When the brake pipepressure is reduced, the triple valve 93 will move to the appliedposition providing auxiliary reservoir 66 pressure to the controlreservoir 65. This flow will cease when the auxiliary reservoir 66pressure has reduced to brake pipe 40 pressure. The triple valve 93 willmove into the lap position. Further reduction of brake pipe will againcause the auxiliary reservoir 66 pressure to flow to the controlreservoir 65 thereby increasing the brake cylinder pressure until theauxiliary reservoir 66 is reduced to the level of the brake pipe 40. Inthis manner, the brake may be gradually applied until equalization ofthe pressure of the combined volume of the auxiliary reservoir 66 andthe control reservoir 65. Any further brake pipe reduction will notincrease the brake cylinder's 66 pressure. Increasing the brake pipe 40pressure will result in immediate complete release of the controlreservoir 65 pressure, and thus release of the brake cylinder pressure.The triple valve 93 will have moved to the release position.

The independent brake control circuit of the brake control portion 62 ofthe interface control valve 60 is illustrated in FIG. 8. The second mainreservoir 48 is connected through a common filter 67 to the independentpressure controller 98 and the actuation pressure controller 99connected respectfully to the independent application and release pipe42 and the actuation pipe 43. These are both electro-pneumatic devicesunder computer control when the locomotive is in a lead mode.Independent application and release pipe pressure sensor 75 andactuation pipe sensor 76 provides feedback signals to the microcomputer56 which in the trailing mode provides appropriate control signal to thecontrol reservoir pressure controller 91. Upon loss of the commandsignal from the microcomputer 56, the independent application andrelease pressure control 98 and the actuating pressure controller 99will lap neither supplying or exhausting pressure from its respectivepipes 42 and 43.

The microcomputer control of the throttle and dynamic braking circuitsis illustrated in FIG. 9. The microcomputer 56 provides throttle anddynamic braking control through the 27-wire trainline 44. The command ofthe 27-wire line is controlled solely through the computer of a leadlocomotive. In the trail mode, the locomotive responds normally to the27-wire line as commanded by another locomotive. The microcomputer 56,in the trail mode, does not directly control power. The microcomputer 56provides and replaces the cam switch interlocks with logic interlocks.

The hump control or power reduction control is an integral feature ofthe equipment. The engineer has a touch sensitive zone for powerreduction on the display. Also the use of local or multiple unit optionis provided on the touch screen 52. If local is selected, the HCR relayis only energized. If the multi-unit selection is made, then the numberone trainline is energized to pick RTL relay as well as the HCR relay.The HCR relay gives control of the number 24 XB trainline to the powerreduction signal. On the initial setup, the minimum reduction of powersignal is given. The engineer then selects, on the touch zone displayscreen 52, the option of lowering or increasing the level of powerreduction. The power reduction will automatically dropout when themaster controller is keyed out.

FIG. 10 illustrates the interface of circuitry for the multi-unitsignalling and sanding of the microcomputer 56. The microcomputer 56will energize the bell trainline 2 through the touch sensitive zone ofthe display 52. The microcomputer 56 also monitors the number 2 SGtrainline to provide a visional indication to the engineer. If the alarmfunction is held for longer than 30 seconds, a message will be shown onthe display. Energizing of the emergency trainline 5ES is a function ofthe microcomputer 56 in the event of an emergency brake application. Thesignal is timed for approximately 30 seconds. The number 23 SA sandingtrainline may be energized through the touch screen display 52. Thistrainline is monitored by the microcomputer 56 to provide a visualindication of the automatic sanding. The brake warning number 20 line ismonitored by the microcomputer for a visual indication of faults. Thewheelslip number 10 line is also monitored by the microcomputer forvisual indication.

The hierarchy or control of the computer 56 is illustrated in FIG. 11and 12. The locomotive control system includes the Initialization Mode1.0, the Control Functions 2.0, the Do Alert Functions 3.0, RecordRunning Data 4.0 and Do Diagnostic 5.0.

The Initialization Mode 1.0 is entered when a unit is turned on. Firstthing a unit must do when it starts up is determine that it can functionproperly. Routine 1.1 checks the system integrity which includes CPUfunctions, the memory units as well as the timer functions. Once thesystem has found to operate properly, it parameters need to beinitialized to values from memory and output set to known states byroutine 1.2. Draw Console screen 1.3 drives the display to known statesand then is drawn with the appropriate areas enabled for touchsensitivity.

The Control Functions 2.0 reads the control inputs from the enginemen,retrieves status information from locomotive equipment and trainlines,then makes decisions about how to control the train and displays thecurrent status on the console. Read control inputs to 2.1 reads inputsfrom the master controller 50, touch screen display 52, the trainlinesand various feedbacks. The master controller 50 is read at 2.1.1, thetrainlines are read at 2.1.2, the auxiliary control console 54 is readat 2.1.3, locomotive feedback signals for example speed, motor current,and switch closures are read at 2.1.4 and end of train status is read at2.1.5.

The Control Locomotive 2.2 determines control requirements for thelocomotive based on the operator inputs and the status of the end oftrain. The appropriate commands for the brake equipment to control thebrake pipe and brake cylinder pressure are produced by the control brakeroutine 2.2.1. These commands will cause the brake equipment to functionlike a 26L type system. Various signals are also sent to safety devicesin the brake equipment. The trainline control routine 2.2.2 energizesthe trainline to control the locomotive propulsion equipment.

Routine 2.3 retrieves status and information on various points of thelocomotive propulsion equipment, the braking equipment and from the endof train unit. System information is analyzed at 2.3.1, alarms aresounded at 2.3.1.1 and the current status of the train is displayed at2.3.1.2. If a break in two detected, the computer by the break in tworoutines 2.4 may retain the locomotive power for a very short period oftime to keep the end of the train from ramming the locomotive during astop.

The Alert Functions under 3.0 monitors the actions of the engineman todetermine that he is alive and in control of train. If the enginemandoes not demonstrate that he is in control, appropriate warning andpenalties will be issued. Routine 3.1, monitors the engineman's actions,with 3.2 providing warning signals. If the operator has not responded tothe warning signals within a predescribed period of time, a penaltyapplication will be enforced under routine 3.3.

Certain locomotive operating conditions such as handle positions, speed,and air pressure will be continuously stored in nonvolatile memory forlater reference under Recording Running Data routine 4.0. Periodicdiagnostic tests are run to determine operational status under routine5.0. Specific tests to be run are run by 5.1 which includes the CPU,clock, and various memories. Current fault status is displayed bysubroutine 5.2. Running data and fault data are sent to a printingdevice by routines 5.3 and 5.4.

The operation of the computer 56 to produce control functions describedabove are illustrated by the flow charts of FIGS. 13, 14 and 15. Thecontrol of the brake pipe is illustrated in FIG. 13. The control of thebrake pipe valve is illustrated in FIG. 14. The control of thelocomotive brake cylinder is illustrated in FIG. 15.

As noted from the software, the pressure for the brake pipe valve isdetermined as a function of the feed valve setting. This assures that anappropriate pressure is provide to apply and release brakes. This may bemanually inputted to the touch display screen as a value, or to a manualpreset value. Also, the model number, capacity or brand name of therelay valves also may be provided, such that an appropriate pneumaticcontrol signal is calculated and provided from, for example, look uptables.

Microcomputer 56 between the master control stand 50 and touch screendisplay 52 and interface control valve 60 allows for a series ofinterlocks to be controlled by the computer and override signalsreceived from the other two devices. Upon determination of an emergencybraking condition from the brake pipe, the microcomputer 56 sets thepropulsion control to an idle condition irrespective of the position ofthe propulsion handle 39. After determination of an emergency braking,the microcomputer 56 will not transmit any propulsion signals until thethrottle handle has been placed in its Idle position.

As a further interlock, the microcomputer 56 will delay transmittingeither propulsion signals or dynamic braking signals when the previoussignal was the opposite or dynamic braking and propulsion respectively.This provides an automatic delay when switching between the propulsionand dynamic braking. When switching between forward and reversedirection, the microcomputer 56 will not transmit reverse propulsionsignals until the train speed is below a predetermined speed. Also, whenswitching back and forth between trailing and leading modes, themicrocomputer 56 will not produce any control signals until theautomatic and independent braking handles 31 and 32 and the throttle 39are in their Neutral or Idle positions. Also when switching betweentrailing and leading, the microcomputer 56 will not provide any signalsuntil the locomotive speed is zero. Also previously mentioned, themicrocomputer 56 will not prepare any propulsion or dynamic brakingsignals when it is in the trailing mode.

Although the present invention has been described and illustrated indetail, it is to be clearly understood that the same is by way ofillustration and example only, and is not to be taken by way oflimitation. The spirit and scope of the present invention are to belimited only by the terms of the appended claims.

What is claimed:
 1. A computerized locomotive control system for alocomotive having a brake pipe, independent application and releasepipe, and an actuating pipe, said system comprising:a control standhaving automatic brake and independent brake handles; means for applyingpneumatically an emergency pressure to said brake pipe when saidautomatic brake handle is in an emergency position; means for convertingpositions of said handles into automatic and independent brakingelectrical signals; and computer means for controlling pressure on saidbrake pipe, independent application and release pipe and actuating pipein response to said braking signals.
 2. A computerized locomotivecontrol system for a locomotive having a brake cylinder, a brake pipeand at least one of the following pipes a) main reservoir equalizationpipe, b) independent application and release pipe and c) actuating pipe,said system comprising:input means for receiving electrical signalsrepresenting braking control signals and electrical signals representingleading and trailing modes in said locomotive; computer means forcontrolling pressure on said pipes in response to said braking controlsignals only in said leading mode and not in said trailing mode; andmeans for controlling said brake cylinder in response to pressure onsaid pipes.
 3. A computerized locomotive control system for a locomotivehaving a brake pipe and at least one of the following pipes a) mainreservoir equalization pipe, b) independent application and release pipeand c) actuating pipe, said system comprising:input means for receivingautomatic and independent braking electrical signals; and computer meansfor controlling pressure on said pipes in response to said brakingsignals and controlling pressure on said brake pipe to at least a fullservice brake pipe pressure for absence of said automatic brakingsignals.
 4. A computerized locomotive control system according to claim3 wherein said computer means controls said independent application andrelease pipe to a brake release pressure for absence of said independentbraking signals.